East Turkestan (also Eastern Turkistan, Chinese Turkestan, and other variants) is a controversial political term with multiple meanings depending on context and usage. Historically, the term was invented by Russian Turkologists in the 19th century to replace the term Chinese Turkestan, which referred to the Tarim Basin in the southwestern part of Xinjiang province of the Qing Dynasty. The medieval Arab toponym "Turkestan" and its derivatives were not used by the local population of the greater region, and China had its own name for an overlapping area since the Han Dynasty as Xiyu, with the parts controlled by China termed Xinjiang from the 18th century onward. The historical Uyghur name is Qurighar (西域; today, Qurighar Uyghur is co-used with Shinjang Uyghur by Uyghurs).

Starting in the 20th century, Uyghur separatists and their supporters used East Turkestan (or "Uyghurstan") as an appellation for the whole of Xinjiang, or for a future independent state in present-day Xinjiang Uyghur Autonomous Region. They reject the name of Xinjiang because of an allegedly Chinese perspective reflected in the name and prefer East Turkestan to emphasize connection to other westerly Turkic groups. However, even in nationalist writing, East Turkestan retained its older, more narrow geographical meaning. In China, the term has negative connotations because of its origins in European colonialism and present use by militant groups. The government of China actively discourages its use.